The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
Dual clutch transmissions (DCT's) are becoming increasingly popular in passenger cars because of their performance and efficiency. Because a gear to be selected for an upshift or downshift can be pre-selected or “pre-staged” before a currently engaged gear is disengaged, the actual upshift or downshift essentially involves simply the disengagement of the engaged clutch and engagement of the disengaged clutch—an operation that can be accomplished in a small fraction of a second. Such rapid shifts lend a highly desirable and sporty performance to the powertrain and the vehicle. Since the dual clutch transmission is essentially a manual transmission incorporating a plurality of pairs of meshed gears and two driveline clutches, fuel economy is also very good. Not only does the dual clutch transmission have fewer components but it also eliminates the torque converter. The dual clutch transmission is thus also less expensive to manufacture than a comparable automatic transmission
Because of its increasing popularity, significant research and development have recently been directed to improving the construction and operation of dual clutch transmissions. A target of such work has been the dual clutch arrangement that selectively and mutually exclusively provides drive torque to the two drive assemblies, usually layshaft or countershafts, in the transmission. Current transmission configurations utilize a pair of essentially identical clutches disposed on the axes of the countershafts or a pair of clutches in tandem which drive concentric shafts.
The current design state of clutch assemblies for dual clutch transmissions suggests that improvements in such clutches are both possible and desirable.